In nuclear strategy, a first strike is a preemptive surprise attack employing overwhelming force. First strike capability is a country's ability to defeat another nuclear power by destroying its arsenal to the point where the attacking country can survive the weakened retaliation while the opposing side is left unable to continue war. The preferred methodology is to attack the opponent's strategic nuclear weapon facilities (missile silos, submarine bases, bomber airfields), command and control sites, and storage depots first. The strategy is called counterforce.

During the Cold War period, both superpowers, NATO and the Eastern Bloc, built massive nuclear arsenals, aimed, to a large extent, at each other. However, they were never used, as after a time, leaders on both sides of the Iron Curtain realized that global thermonuclear war would not be in either power's interest, as it would probably lead to the destruction of both sides, and possibly nuclear winter or other extinction level events.[citation needed] Therefore, at times, both sides refrained from deploying systems capable of unanswerable nuclear strikes against either side. However, in both nations, there were interests that benefited from the development and maintenance of first-strike weapons systems: what U.S. President Dwight Eisenhower termed the military-industrial complex; these forces encouraged the constant development of weapons systems of greater accuracy, power, and destruction. In addition, each side doubted the other side's commitment to not deploy first-strike weapons, or even in the event of their deployment, to not strike first. Some first-strike weapons were deployed; however like most nuclear weapons, they were never used.

Of the nuclear powers, only the People's Republic of China and the Republic of India have declarative, unqualified, unconditional no-first-use policies. In 1982, at a special session of the General Assembly of United Nations, the USSR pledged not to use nuclear weapons first, regardless of whether its opponents possessed nuclear weapons or not. This pledge was later abandoned by post-Soviet Russia to compensate the overwhelming conventional weapon superiority enjoyed by NATO. The United States has a partial, qualified no-first-use policy, stating that they will not use nuclear weapons against states that do not possess nuclear weapons or other weapons of mass destruction.

Large-scale missile defense systems are not first-strike weapons, but certain critics view them as first-strike enabling weapons. U.S. President Ronald Reagan's proposed Strategic Defense Initiative, if it had ever been deployed (and proven successful), would have undermined the fundamental premise of mutual assured destruction (the inevitable outcome of equal and unacceptable destruction for both sides in the event of nuclear war), removing the incentive for the US not to strike first.

These proposed defense systems, intended to lessen the risk of devastating nuclear war, would lead to it, according to these critics. Indeed, according to game theory, the side not building large-scale missile defenses would have an incentive to launch a pre-emptive first strike while such a strike could still get through.

First-strike attack, the use of a nuclear first strike capability, was greatly feared during the Cold War between NATO and the Soviet Bloc. At various points, fear of a first strike attack existed on both sides. Misunderstood changes in posture and well understood changes in technology used by either side often led to speculation regarding the enemy's intentions.

In the immediate aftermath of World War II, the leadership of the Soviet Union feared the United States would use its nuclear superiority to its advantage, as from 1945 to 1948 the U.S. was the only state possessing nuclear weapons. The USSR countered by rapidly developing their own nuclear weapons, surprising the US with their first test in 1949. In turn, the U.S. countered by developing the vastly more powerful thermonuclear weapon, testing their first hydrogen bomb in 1952 at Ivy Mike, but the USSR quickly countered by testing their own thermonuclear weapons, with a test in 1953 of a semi-thermonuclear weapon of the Sloika design, and in 1956, with the testing of Sakharov's Third Idea – equivalent to the Castle Bravo device. Meanwhile, tensions between the two nations rose as 1956 saw the suppression of Hungary by the Soviets; the U.S. and European nations drew certain conclusions from that event, while in the U.S., a powerful social backlash was afoot, prompted by Senator Joseph McCarthy, the House Un-American Activities Committee, and Julius and Ethel Rosenberg, two atomic spies. This atmosphere was further inflamed by the 1957 launch of Sputnik, which led to fears of Communists attacking from space, as well as concerns that if the Soviets could launch a device into orbit, they could equally cause a device to re-enter the atmosphere and impact any part of the planet. John F. Kennedy capitalized on this situation by emphasizing the Bomber gap and the Missile Gap, areas in which the Soviets were (inaccurately) perceived as leading the United States, while heated Soviet rhetoric, including Soviet Premier Nikita Khrushchev's famous threat that "We will bury you!" to Western ambassadors added to political pressure. The 1960 U-2 incident, involving Francis Gary Powers, as well as the Berlin Crisis, along with the test of the Tsar Bomba, escalated tensions still further.

This escalating situation came to a head with the Cuban Missile Crisis of 1962. The arrival of Soviet missiles in Cuba was conducted by the Soviets on the rationale that the US already had nuclear missiles stationed in Turkey, as well as the desire by Fidel Castro to increase his power, his freedom of action, and to protect his government from US-initiated prejudicial resolution of ideological disputes through the use of military force, such as had been attempted during the Bay of Pigs Invasion in April 1961. During the crisis, Fidel Castro wrote Khrushchev a letter about the prospect that the "imperialists" would be "extremely dangerous" if they responded militarily to the Soviet stationing of nuclear missiles aimed at US territory, less than 90 miles away in Cuba. The following quotation from the letter suggests that Castro was calling for a Soviet first strike against the US if it responded militarily to the placement of nuclear missiles aimed at the US in Cuba:

"If the second variant takes place and the imperialists invade Cuba with the aim of occupying it, the dangers of their aggressive policy are so great that after such an invasion the Soviet Union must never allow circumstances in which the imperialists could carry out a nuclear first strike against it. I tell you this because I believe that the imperialists' aggressiveness makes them extremely dangerous, and that if they manage to carry out an invasion of Cuba—a brutal act in violation of universal and moral law—then that would be the moment to eliminate this danger forever, in an act of the most legitimate self-defense. However harsh and terrible the solution, there would be no other."[1]

The Cuban Missile Crisis resulted in Khrushchev publicly agreeing to remove the missiles from Cuba, while Kennedy secretly agreed to remove his country's missiles from Turkey. Both sides in the Cold War realized how close they came to nuclear war over Cuba, and decided to seek a reduction of tensions, resulting in US-Soviet détente for most of the 1960s and 1970s.

Nonetheless, this reduction of tensions only applied to the US and the USSR. Recently declassified interviews with high level former Soviet nuclear and military-industrial planners reveal that Fidel Castro continued to favour nuclear options, even during the later Cold War – according to former Soviet General Danilevich, "(...in the early 1980s...) Cuban leader Fidel Castro pressed the USSR to take a tougher line against the United States, including possible nuclear strikes. The Soviet Union, in response, sent experts to spell out for Castro the ecological consequences for Cuba of nuclear strikes on the United States. Castro, according to the General, was quickly convinced to the undesirability of such outcomes."[2]

However, tensions were inflamed again in the late 1970s and early 1980s with the Soviet invasion of Afghanistan, the Soviet deployment of the SS-20 Saber and the SS-18 Satan, and the decision of NATO to deploy the new Pershing IIIRBM as well as the TomahawkGround Launched Cruise Missile, along with U.S. President Ronald Reagan's talk of 'limited' nuclear war. This increased Soviet fears that NATO was planning an attack. NATO's deployment of these missiles was a response to the Soviet deployment of the SS-20 Saber, which could hit most European NATO bases within minutes of launch. These mutual deployments led to a destabilizing strategic situation, which was exacerbated by malfunctioning U.S. and Soviet missile launch early warning systems, a Soviet intelligence gap that prevented the Soviets from getting a "read" on the strategic intentions of U.S. leaders, as well as inflammatory U.S. rhetoric combined with classical Soviet mistrust of the NATO powers. This culminated in a war scare that occurred during 1983 due to the inopportune timing of a NATO exercise called Able Archer, which was a simulation of a NATO nuclear attack on the Soviet Union; this exercise happened to occur during a massive Soviet intelligence mobilization called VRYAN, that was designed to discover intentions of NATO to initiate a nuclear first-strike. This poor timing drove the world very close to nuclear war, possibly even closer than the Cuban Missile Crisis over 20 years before.

Subsequent events caused the fears of nuclear attack on both sides to diminish significantly, as the tensions between the superpowers decreased, and have remained—at least in nuclear terms—comparatively low. However, the present indicates that this might be changing. Relations between the two have recently fallen to new post–Cold War lows, and events have illustrated that the world may be heading back towards a more tense situation in terms of nuclear armament and use, possibly even to a first strike. Talk that has been characterized as "reckless"[by whom?] has been rife amongst certain U.S. politicians who favor the development of new nuclear weapons (such as through the Complex 2030 program) or new uses for old weapons, such as by using them as nuclear bunker busters, even against non-nuclear states. The military invasion of Iraq was seen by the Russian leadership as indicating potential U.S. disrespect for what the Russian leadership views as international law. The U.S. missile defense program has proven to be the primary persistent obstacle to better relations with Russia, which views the placement of U.S. missile defense systems in Eastern Europe for defense against "the Iranian threat" similarly to how the U.S. would view placement of Russian missile defense systems in, for example, Cuba, for Russian defense against "the insidious Asian". The assassination of a British citizen by alleged operatives of the Russian government using Polonium-210, a radioactive poison, as well as the alleged dioxin poisoning of the President of the Ukraine, has raised tensions between Russia and the West, with some commentators in Western nations regarding the poisonings as an indicator of the character and true intentions of the Kremlin. Western nations view Russian bellicosity and belligerence as having markedly increased as of late, with tests of new nuclear-capable missiles occurring on a regular basis, military conflicts with neighboring states, claims of a Russian "sphere of influence" on the perimeter of the old Soviet Union, the rise of ultra-nationalist "Putin Youth" groups, aggressive politicization of and threats of withdrawal of natural gas supplies to Europe should the Europeans not make certain policy concessions, and even threats of a nuclear first strike against Poland have been heard to be made by certain Russian generals.

Even with these developments, recent events in both nations have served to restrain rhetoric and action in the direction of strategic destabilization, and have encouraged the possibility of stabilizing developments. Both the US and Russia have suffered economic problems as a result of the recent economic crisis and both are seeking to retrench policies that are viewed as potentially costly or reckless between the two. Russia's military development is no longer backed and inflated by the record-high natural gas and oil prices that formerly allowed massive sums to be poured into military spending while US arms buildups are no longer encouraged by the previous Administration. Indeed, the correlation of forces and means between the two suggests the possibility of a potential reciprocal nuclear weapon drawdown to low levels consistent with minimum credible deterrence – and, beyond that – to ultimate levels comparable with the nuclear force levels of the other great powers – achievable within the next decade. Both nations have begun to realize the core truth of the post–Cold War era that, if the strategic reality, as described by the words of Ronald Reagan, is that "Nuclear war cannot be won and must not be fought", then large nuclear weapons stockpiles have no positive use, are expensive, and can lead to dangerous destabilization. The possibility of a peace with honor of strategic equals between Russia and the US may now be possible.

Still, strategic problems remain in other areas. Other nations have engaged in policies that are regarded as potentially destabilizing. Officials in the People's Republic of China recently tested an anti-satellite missile, leading to widespread international concern, as anti-satellite missiles are viewed as threats to nuclear-launch warning systems, which could facilitate a first strike; further, tensions amid the Chinese governments over Taiwan have been rife in recent years; in addition, the PRC is reportedly pursuing modernization of their nuclear forces. Israel has made threats of the use of weapons, including those of a non-conventional character, while the former administration in the U.S. has refused to "take options off the table" (including the "nuclear option"), in the nuclear dispute with Iran, which is widely viewed as pursuing a clandestine nuclear weapons program, and well known for their desire for the destruction of Israel (c.f. "The World Without Israel") and extreme dislike for the United States (c.f. regular political rallies in Tehran calling for "Death to America!"). The unpredictable North Korean government has tested (or, more likely, partially fizzled) a nuclear device, and has historically threatened to turn Seoul into a "sea of fire", or most recently, "ashes", in response to unspecified, but always imminent, U.S. or South Korean "aggression" against it. The foreign relations of Pakistan and India remain unstable, but are now exacerbated by the nuclear arsenals of both states, as well as the rise of political parties promoting Hindu nationalism in India, and the rise of al-Qaeda Islamism in Pakistan, as well as intercommunal strife—ranging from the demolition of a historic mosque by communal hooligans with worshipers inside to a terrorist assault on Hindu shrines—could set off a nuclear war.

Neither side sought nuclear conflict, even though it threatened to break out on multiple occasions. What both sides had, however, was a deep and continuing fear that the other nation was seeking to start a nuclear conflict, or, at least, thought such a conflict was "winnable" and would not be deterred by the threat of nuclear war. This led to both sides adopting aggressive, confrontational military and nuclear strategies that were misinterpreted and countered by the other side, furthering distrust. These strategies led to destabilization of the strategic situation to the point where the two major war scares of the Cold War occurred: the Cuban Missile Crisis and the Able Archer/VRYAN crisis. Though neither side intended to start a nuclear war, and, in fact, were extremely concerned about the possibility of it, neither side adopted strategies to calm things down, so sure were they of their adversaries' bad faith.

U.S. military strategy (at least in Europe) was confined to responses to potential Soviet aggression against NATO countries. Soviet military theory was dominated by the theory of the "deep operation" – a large-scale combined-arms offensive into enemy-held territory – rather than a nuclear offensive. Soviet conventional superiority, shown by the fact that the Soviet Union certainly was prepared for war in Europe, having massed armored, mechanized, artillery, and air forces poised along the Inner German and Czech borders, led by the dreaded Third Shock Army of the Soviet Union, caused NATO to consider the use of tactical nuclear weapons to stop the "steamroller" of the Red Army if they decided to take a drive through the Fulda Gap or an amble through the North German Plain. NATO's position changed in the 1970s and 1980s, in favor of trying to stop a Soviet offensive through the employment, at least initially, of a doctrine involving non-nuclear AirLand Battle to try to buy time to either throw back the invader or work out the issues at hand through diplomacy. Both sides, however, were willing to use nuclear weapons, if necessary, to not lose the war at hand. Although neither side was actively pursuing a first-strike policy—since the time of Khrushchev, the leaders of orthodox communism believed that "peaceful coexistence" with the "imperialist" powers was possible—both sides relied on military strategies that could have still caused a general nuclear war.

Ideological determinism also played a role. President Ronald Reagan of the United States, at least before the Able Archer/VRYAN crisis, believed that everybody, including the Soviet Union, was completely aware of the United States' good intentions, even when he bellicosely declared that the USSR was an "evil empire" and (more jokingly) that the "bombing begins in 5 minutes" while encouraging the military to conduct threatening exercises, such as sneaking a Carrier Battle Group through the GIUK Gap and sending nuclear-capable bombers towards the territory of the USSR. Chairman Yuri Andropov of the Soviet Union had similar, distorted views; he believed that the Western Allies, and the U.S., in particular, were fascist states, whose leaders had territorial designs against the Soviet Motherland on the scale of Napoleon I, at the least, and Adolf Hitler, at the worst; in addition, to counter the "fascists", he incited his military-industrial complex to build weapons such as the SS-20MIRVIRBM and the SS-18 Satan MIRV ICBM, which the NATO countries reasonably viewed as a Soviet sword against their throats, and caused reaction through development of equivalent or superior weapons systems.

When the superpowers drew close to the edge of the nuclear abyss during both the Cuban Missile Crisis and the Able Archer/VRYAN Crisis, they learned and grew from their mistakes and miscalculations that led them to be within view of mutual assured destruction. Andropov was followed as Soviet leader by Konstantin Chernenko, who in turn was followed by Mikhail Gorbachev, and Gorbachev brought a far less hostile, ideological, and reflexively skeptical approach to the relations between the superpowers, helping to build an atmosphere of trust between the two. Reagan had a figurative conversion on the road to Damascus regarding nuclear weapons and (especially) ICBMs following this crisis, discarding his preconceived notions of general Soviet bad faith, leading him to come full circle and famously declare that "Nuclear war cannot be won and must not be fought". These new attitudes on both sides nearly brought about the disarmament and destruction of ICBMs, long-range SLBMs, and, possibly even nuclear weapons themselves at a groundbreaking disarmament summit between Gorbachev and Reagan at Reykjavík in 1986. (The sticking point causing agreement to be unreachable was the SDI Program, just as missile defense continues to be a thorn in the side of the Russians today.) However, progress was made; the INF Treaty, the Conventional Forces in Europe Treaty, and the START Treaty could be said to be the result of the change in leaders and leaders' attitudes that the Able Archer/VRYAN crisis facilitated, just as the Non-Proliferation Treaty and the Partial Test Ban Treaty, as well as U.S.-Soviet détente, could be considered to be the sons and daughters of the Cuban Missile Crisis. Still, both crises were dangerous times catalyzed by dangerous political and military mistakes caused by dangerous policies instituted by leaders who let their fear get the better of their judgment and reasoning. Thankfully for those who lived, and those who now live, these mistakes never caused a first strike to come to pass.

CEP – circular error probable; the radius within which a weapon aimed at a given point will land with a 50% confidence; for example, a CEP of 150 m indicates that 50% of the time, the weapon will impact within 150 m of the target. This measure of accuracy assumes that everything up to the point of impact works correctly.

Range – the maximum distance from a target a weapon can be fired to successfully hit the point where it is targeted at. (When range is used without qualifiers, like maximum or minimum, it is assumed that it refers to maximum; however, many of these described weapons have minimum ranges as well, though they are not mentioned, or, in all likelihood, even known to the public.)

kt/Mt – This is an approximate measure of how much energy is released by the detonation of a nuclear weapon; kt stands for kilotonsTNT, Mt stands for megatons TNT. Conventional science of the period contemporary to the Manhattan project came up with these measures so as to reasonably analogize the incredible energy of a nuclear detonation in a form that would be understandable to the military, politicians, or civilians. Trinitrotoluene (TNT) was and is a high explosive with industrial and military uses, and is around 40% more powerfully explosive than an equivalent weight of gunpowder. A ton is equivalent to 1000 kg or approximately 2000 American pounds. A 20 kt nuclear device, therefore, liberates as much energy as does the explosion of 20,000 tons of TNT (this is the origin of the term, for the exact definition see TNT equivalent). This is a large quantity of energy. In addition, unlike TNT, the detonation of a nuclear device also emits ionizing radiation that can harm living organisms, including humans; the prompt radiation from the blast itself and the fallout can persist for a long period of time, though within hours to weeks, the radiation from a single nuclear detonation will drop enough to permit humans to remain at the site of the blast indefinitely without incurring acute fatal exposure to radiation.

Because of the low accuracy (Circular error probable) of early generation Intercontinental ballistic missiles (and especially Submarine-launched ballistic missiles), counterforce strikes were initially only possible against very large, undefended targets like bomber airfields and naval bases. Later generation missiles with much improved accuracy made counterforce attacks against the opponent's hardened military facilities (like missile silos and command and control centers) possible. This is due to the inverse-square law, which predicts that the amount of energy dispersed from a single point release of energy (such as a thermonuclear blast) dissipates by the inverse of the square of distance from the single point of release. The result is that the power of a nuclear explosion to rupture hardened structures is greatly decreased by the distance from the impact point of the nuclear weapon. So a near-direct hit is generally necessary, as only diminishing returns are gained by increasing bomb power.

Pershing IIIRBM. Single warhead, variable yield 5-50 kt, CEP 50 m with active radar terminal guidance. Short, 7-minute flight-time and range of 1,800 km, designed to strike C4ISTAR installations, bunkers, air fields, air defense sites, and ICBM silos in the European part of the Soviet Union. Decommissioned.

SS-18 SatanMIRV—Believed to be a first-strike weapon by some in the West, due to high accuracy of 220 m CEP, and high throw-weight of 8,800 kg; could deploy 40 penetration aids and deliver at least 10 warheads of at least 500 kt to independent, separate targets. Each warhead could probably take out even hardened nuclear silos, such as those used by the Minuteman III. Deployed in 1976, aimed at CONUS. Still in service.

LGM-118 Peacekeeper—Similar in capability to the SS-18 Satan, the Peacekeeper had a throw-weight of 4,000 kg, and could carry only 10 MIRVed warheads of 300 kt each, as well as a CEP of 120 meters. Deployed in the mid-1980s. Decommissioned; however, guidance systems and re-entry vehicles moved to Minuteman III missiles.

SS-20 Saber MIRV IRBM—Deployed by the Soviet Union in the late 1970s, this MIRVed IRBM could hide out behind the Urals in Asian Russia and strike NATO C4ISTAR facilities in Europe with scarcely any warning, due to very short flight time, high accuracy, and MIRV payload (rare on an intermediate-range missile). Decommissioned.

Any missile defense system capable of wide-area (e.g. continental) coverage, and especially those enabling destruction of missiles in the boost phase, are first-strike-enabling weapons because they allow for a nuclear strike to be launched with reduced fear of mutual assured destruction. Such a system has never been deployed, although a limited continental missile defense capability has been deployed by the U.S., but is capable of defending against only a handful of missiles.

This does not apply, in general, to terminal missile defense systems, such as the former U.S. Safeguard Program or the Russian A-35/A-135 systems. Limited-area terminal missile defense systems, defending such targets as ICBM fields, or C4ISTAR facilities may, in fact, be stabilizing, because they ensure survivable retaliatory capacity, and/or survivable de-escalation capacity.

This also might not apply to a "non-discriminatory" space-based missile defense system, even if it is—actually, precisely because it is—of global reach. Such a system would be designed to destroy all weapons launched by any nation in a ballistic trajectory, negating any nation's capability to launch any strike with ballistic missiles, assuming the system was sufficiently robust to repel attacks from all potential threats, and built to open standards openly agreed upon and adhered to. No such system has yet been seriously proposed.

UGM-133 Trident II. Trident missiles may carry up to 8 100kt W76 (C4) or 12 (START-limited 8, SORT-limited 5) W76 or 475kt W88 MIRVed warheads (D5), The circular error probable of these weapons is classified, but is believed to be less than 120m (C4) and 100m (D5). The missile attains a temporary low altitude orbit only a few minutes after launch. The Guidance System for the missile is an Inertial Guidance System with an additional Star-Sighting system, which is used to correct small positional errors that have accrued during the flight. GPS has been used on some test flights but is assumed not to be available for a real mission. Trident I-C4 has a range of over 4,000 nm while the Trident II-D5 can surpass 6,000 nm; however, the absolute ranges of these missiles are classified and withheld from public domain for reasons of national security.

SS-18 Satan Mod I/II 25 megaton variant. Although it is widely accepted that USSR never had a first-strike strategy (due to its conventional arms superiority in Europe), some experts[who?] believed that the single-warhead 25 megaton version of R36-M (SS-18, CEP 250 m.) was a first-strike weapon, targeted against Minuteman III silos. However, a much more logical explanation comes from retired Soviet military officers who report that the 25 megaton SS-18 was targeted against heavily fortified command and control facilities. The reason for this is that a single 25 megaton warhead could take out only one hardened missile silo if the silos are sufficiently separated—probably by only 2–4 km, depending on the amount of hardening. This is due to the inverse square law, which predicts that the amount of energy dispersed from a single point release of energy (such as a thermonuclear blast) dissipates by the inverse of the square of distance from the single point of release. The result is that the power of a nuclear explosion to rupture hardened structures is greatly decreased by the distance from the impact point of the nuclear weapon. So a near-direct hit is generally necessary, as only diminishing returns are gained by increasing bomb power. The only purpose for gigantic nuclear weapons, like the SS-18 25 megaton variant, is to take out extremely hardened targets, like command and control facilities, such as NORAD, located at Cheyenne Mountain; Federal Emergency Management Agency (FEMA), located at Mount Weather; or Site R, located at Raven Rock. (It should be noted that the amount of energy needed to rupture missile silos is orders of magnitude greater than the amount necessary to destroy cities, making the SS-18 25 megaton variant effective for the destruction of large urban centers, as well.) This could be a useful weapon for a decapitation strike—however, a decapitation strike is a very risky move, and both the U.S. and Russia have extensive countermeasures against such methods.

According to the theory of nuclear deterrence and mutually assured destruction, full countervalue retaliation would be the likely fate for anyone who unleashed a first strike. So as to maintain credible deterrence, the nuclear-weapons states have taken measures to give their enemies reason to believe that a first strike would lead to unacceptable results.

The main strategy here relies on creating doubt among enemy strategists regarding nuclear capacity, weapons characteristics, facility and infrastructure vulnerability, early warning systems, intelligence penetration, strategic plans, and political will. In terms of military capabilities, the aim is to create the impression of the maximum possible force and survivability, leading the enemy to make increased estimates of the probability of a disabling counterstrike; while in terms of strategy and politics, the aim is to cause the enemy to believe that such a second strike would be forthcoming in the event of a nuclear attack.

Nuclear-powered ballistic missile submarines (SSBNs) carrying submarine-launched ballistic missiles (SLBMs), commonly known as "boomers" in the US and "bombers" in the UK, are widely considered the most survivable component of the nuclear triad. The depths of the ocean are extremely large, and nuclear submarines are highly mobile, very quiet, have virtually unlimited range, and can generate their own oxygen and potable water; in essence, their undersea endurance is limited only by food supply. It is unlikely that any conceivable opponent of any nuclear power deploying ballistic missile submarines could locate and neutralize every ballistic missile submarine before it could launch a retaliatory strike, in the event of war. Therefore, to increase the percentage of nuclear forces surviving a first strike, a nation can simply increase SSBN deployment, as well as deployment of reliable communications links with SSBNs.

In addition, land-based ICBM silos can be hardened. No missile launch facility can really defend against a direct nuclear hit, but a sufficiently hardened silo could defend against a near miss, especially if the detonation is not from a multimegaton thermonuclear weapon. In addition, ICBMs can be placed on road or rail-mobile launchers (RT-23 Molodets, RT-2PM2 Topol-M, DF-31, MGM-134 Midgetman), which can then be moved around; as an enemy has nothing fixed to aim at, this increases their survivability.

The effectiveness of a first strike is contingent upon the aggressor's ability to immediately deplete its enemy's retaliatory capacity to a level that would make a second strike impossible, mitigable, or strategically undesirable. Intelligence and early warning systems increase the probability that the enemy will have the time to launch its own strike before its warmaking capacity has been significantly reduced, thus rendering a first strike pointless. Alert states such as DEFCON conditions, apart from serving a purpose in the internal management of a country's military, can have the effect of advising a potential aggressor that an escalation towards first strike has been detected, and therefore that effective retaliatory strikes could be made in the event of an attack.

Looking Glass, Nightwatch, and TACAMO are U.S. airborne nuclear command posts, and represent survivable communication links with U.S. nuclear forces. In the event of significant political-military tensions between the nuclear powers, they would take to the skies, and provide survivable communications in the event of enemy attack. They are capable of the full exercise of all available MAOs (Major Attack Options), as well as the full SIOP, in the event of a first strike, or the destruction of the NCA. They can directly initiate launch of all U.S. ICBMs via radio and satellite communication, signal SLBMs to launch, and send bombers on their strike missions. In addition to these airborne assets, the U.S. government has several command and control bunkers, the most famous of which is NORAD, tunneled a few thousand feet into the granite of Cheyenne Mountain, outside of Colorado Springs, Colorado, which is believed to be capable of withstanding and continuing to operate after a nuclear direct hit. Other U.S. C4ISTAR bunkers include an installation called Site R, located at Raven Rock, Pennsylvania, which is believed to be the Pentagon's relocation site if Washington, D.C. is destroyed, as well as Mount Weather, in Virginia, which is believed to be the relocation site for top Executive Branch officials. The Greenbrier in West Virginia was once the site of the Supreme Court of the United States and Congress' relocation bunker; however, it is no longer a secret and is now a tourist attraction.

The Russians also have equivalent or superior capabilities in this area; they have a system called SPRN (СПРН), which is capable of detecting nuclear launches and providing early warning, so that any such strike would not be undetected until it is too late. But their unique and special capability can be found with their Dead Handfail-deadly computerized nuclear release system,[3] based at Mount Yamantaw in the Urals. Apparently, Dead Hand, named for either the Dead Man's Hand in poker, or the Dead Man's Switch in dangerous or deadly machinery, can be turned on in the event that the Russian leadership fears a nuclear attack. Allegedly, once Dead Hand is activated, if it detects a loss of communications with Moscow as well as nuclear detonations inside of Russian territory, it can give final authority for the release of nuclear weapons to military officers in a bunker under Mt. Yamantaw, who can then, if they so determine, launch Russia's arsenal. Mt. Yamantaw is believed to be able to withstand multiple direct nuclear detonations.

Instead of relying on sophisticated communications links and launch-on-warning postures, the French, British, and Chinese have chosen to assume different nuclear postures more suited to minimum credible deterrence, or the capability to inflict unacceptable losses so as to prevent the use of nuclear weapons against them, rather than pursuing types of nuclear weapons suitable to first-strike use.

The People's Republic of China is believed to pursue a minimum credible deterrent/second strike strategy with regards to the United States. This may or may not be true with regards to the PRC's stance vis a vis Russia, as the majority of Chinese nuclear platforms are non-intercontinental, and are deployed on the Russian-Chinese border. Unlike the relations of the United States and the PRC, the PRC and Russia have had military conflicts in the past. In recent years, the PRC has improved its early-warning systems and renovated certain of its platforms for intercontinental strike; this may be due to the U.S. missile defense system (it may not be, however). In general, it appears that the PRC's leaders do not greatly fear a first strike (due to their posture of merely inflicting unacceptable losses upon an adversary as opposed to the U.S./Russian policy of trying to "win" a nuclear war); in any event, the Chinese arsenal is considered sufficient to ensure that such a first strike would not go unavenged.

The United Kingdom and France possess sophisticated nuclear weapons platforms; however their nuclear strategies are minimum credible deterrent-based. Each possesses ballistic missile submarines armed with intercontinental submarine-launched ballistic missiles to ensure a devastating second strike retaliation anywhere in the world. France also possesses a number of nuclear capable fighter aircraft. Both countries' nuclear policies are believed to be that of effective deterrence towards a would be nuclear strike against themselves, NATO, European Union members and other allies.

MIRVed land-based ICBMs are considered destabilizing because they tend to put a premium on striking first. When a missile is MIRVed, it is able to carry many warheads (up to 8 in existing U.S. missiles, limited by New START, though Trident II is capable of carrying up to 12[4]) and deliver them to separate targets. If it is assumed that each side has 100 missiles, with 5 warheads each, and further that each side has a 95 percent chance of neutralizing the opponent's missiles in their silos by firing 2 warheads at each silo, then the attacking side can reduce the enemy ICBM force from 100 missiles to about 5 by firing 40 missiles with 200 warheads, and keeping the rest of 60 missiles in reserve. As such, this type of weapon was intended to be banned under the START II agreement, however the START II agreement was never activated, and neither Russia nor the USA has adhered to the agreement.

Any defense system against nuclear missiles such as SDI will be more effective against limited numbers of missiles launched. At very small numbers of targets, each defensive asset will be able to take multiple shots at each warhead, and a high kill ratio could be achieved easily. As the number of targets increases, the defensive network becomes "saturated" as each asset must target and destroy more and more warheads in the same window of time. Eventually the system will reach a maximum number of targets destroyed and after this point all additional warheads will penetrate the defenses. This leads to several destabilizing effects.

First, a state that is not building similar defenses may be encouraged to attack before the system is in place, essentially starting the war while there is no clear advantage instead of waiting until they will be at a distinct disadvantage after the defenses are completed. Second, one of the easiest ways to counter any proposed defenses is to simply build more warheads and missiles, reaching that saturation point sooner and hitting targets through a strategy of attrition. Third, and most importantly, since defenses are more effective against small numbers of warheads, a nation with a defense system is actually encouraged to engage in a counterforce first strike. The smaller retaliatory strike is then more easily destroyed by the defense system than a full attack would be. This undermines the doctrine of MAD by discrediting a nation's ability to punish any aggressor with a lethal retaliatory second strike.

The movie and the book The Hunt for Red October involves the fear of a Russian submarine nuclear delivery system that is so ideal for a first strike that its captain and others plan to defect with the submarine rather than allow it to continue under Russian control.